Francis herbert wenham



P.H.WENHAM. HOT AIR ENGINE.

No. 81,853. Patented Sept. 1. 1868 www -uitel tetes get-tent ffice.

FRANCIS HERBERT WENHAM, OF LONDON, ENGLAND, ASSIGNOR TO ANDREW SHANKS.

Letter Patent No. 81,85'3, dated September 1, 1868.

IMPROVEMENT IN HOT-AIR ENGINES.

fiile tlgcimlr rrfemz tu in tlgise Enters @anni :mi making part sf tlg same.

TO ALL WHOM' I'I MAY ,GONCERNz I Be it known that I, Fl'tANcIs HEnnERT WENHAM, of London, England, have invented certain new and useful Improvements in Heated-Air Engines 3" and Ido hereby declaro that the following is a full and exact description thereof, reference being had to the accompanying sheet of drawings, forming a part of this specification.

The said invention cousistsclxielly in such a construction andai-rangement of the parts of the engine, that in a snglecylinder the piston is acted ou in both directions, that is, the stroke of the piston in one direction is `produced by'vthe heated air from the furnace, while in the other direction the piston is impelled by the expansion o'f abody of air which` is retained and compressed ahovethe piston.

yThe capacity ofthe cylinder must be such that the air required to ll the same is more than tho quantity required to be supplied to the furnace at each strokoof the piston. I prefer to construct the engine with a. vertical cylinder, of such length that a space is left above the pistnn, when the same is et the end of its upward stroke, and a large portion of the air in the cylinder, instead of being forced into the furnace at each stroke of the piston, is retained and compressed into this space, and, by its subsequent expansion, nots upon the pistou in its downward stroke. The action of the piston, throughout its upward and downward strokegis thus equalined, and the engine will work much more advantageously than when' the power is exerted only on one side of the piston, as has hitherto been the case in heated-air engines of a single cylinder.

Description Qf the Drawings.

Figure 1 is a longitudinal section of my improved engine and furnace.

Figure 2 is a section on the line :c x, iig. 1.

Figure 3 is a plan of part of the furnace.

Like letters indicate the same parte in all of the gures.

I make the upper ond of thocyliuder, a, of such capacity that, when the piston reaches the top of the stroke at c, a space,.d, isleft, in which the portion of air not required may be compressed, and consequently will'not enter the-furnace, and by its subsequent expansion willA assist the down( stroke of the piston. This space may be formedhetween the piston and cylinder-cover, or the air may be compressed in a side-passage or reservoir.

In this engine I prefer-carrying the crank-shaft, e, in bearings bolted to the top of the ange of the cylinder, and working the crank hy the connecting-rod,f, with the guidesf for the piston-rods labove, similar in form to that known as tho stceplo-engine. l

The stove ghas s partition near the grate h. Abve this is a feeding-tube or hopper, z', bolted to the lid of the stove, where it is closed and made air-tight by a metal stopper, j. There is a similary stopper, k, beneath the grate, for the removal of ashes. The hopper descends to within about three inches of the grate, and should contain enough fuel for several hours work. The fuel descends by its own weight as itis burned, and all products of combustion having to pass through previously-ignited fuel, the smoke is thus consumed. The airpassage, Z, lending from the top of vthe cylinder, enters the furnace both above and below the grate h. There is nn inner loose ring within the stove, forming an-annulsr space, and the s'tove. is lined with hre-brick, which prevents thc outside from being overheated. Cold air maybe admitted into this annular space, to further .pre vent overheating. v Every stroke of the piston discharges the air from its upper side, through tho passages Z, linto the stove. The expanded airis conveyed by al pipe, m, from tho top of the stove to the valve-chcst n, where it is admitted beneath the piston, which is forced upward by its pressure` The disk o, which is shown detached in iig. 3, is formed of tire-clay. This disk is placed over the furnace, and is supportedon thc Hang@ of the fire-pan, its central aperture being equal in diameter to the here of the fuel-hopper z', whose lower end rests on the said disk. The bottom edge of the hopper is thus protected from the direct heat of the re. Holes or pcrforations, o', are formed through the outer portion of the disk, and lead from thegrnte 'into the annular space g of the stove'. jet of puro flame rises through each of these perrations at every stroke of the engine, and at the same time the tire is kept from rising above its proper eig it.

The valves, through which the nir cnters'aml leaves the cylinder, are of the puppet kind. Both the inlet and exhaust are worked direct from the crunk-shaft'by cams p. The looped upper ends of the valvereds embrace the shaft, and are provided with rollers running on the said cams.

` The speed of the engine muy be regulated by'conneeting the governor with u vulve set in the air-pump passage or cover, or more or less cold air may be sent into the upper or lower space in the stove g by a throttlevulve, worked by the governor, which valve willopen or close either the upper or lower passage,a.rd thus regulate the combustion of the fuel, according to-the power requiredvto work the engine.

What I claim, anddesre to secure by Letters Patent, is-

The cylinder constructed as herein set forth, whereby a. portion of air admitted into the cylinder is retained and compressed ebove the piston at euch upward stroke of the same, substantially as set forth.

2. The arrangement of the furnalee g, wit-l1 the hopper -z and grate 71., constructed with reference to the cylinder a, substantially ns hereinset forth.

3. The fire-clay disk '0, constructed und fitted inthe furnace, substantially as and for the purposes set forth.

' FRANCIS HERBERT WENHAM. [.L. s.]

vWitnesses:

Tos. T. WALMER,

Gnome HAsEL'rrNE, 8 Southampton Buildings, Loudon, W. 0'., England. 

